1. Field of the Invention
The present invention concerns computer systems in general, and the management of platform firmware in particular.
2. Background Information
Computer platform firmware is used during initialization of computer systems to verify system integrity and configuration. It also generally provides the basic low-level interface between hardware and software components of those computer systems, enabling specific hardware functions to be implemented via execution of higher-level software instructions contains in computer programs that run on the computer systems. In computers, a primary portion of this firmware is known as the Basic Input/Output System (BIOS) code of a computer system. The BIOS code comprises a set of permanently recorded (or semi-permanently recorded in the case of systems that use Flash Memory BIOS) software routines that provides the system with its fundamental operational characteristics, including instructions telling the computer how to test itself when it is turned on, and how to determine the configurations for various of built-in components and add-on peripherals.
In a typical PC architecture, the BIOS is generally defined as the firmware that runs between the processor reset and the first instruction of the Operating System (OS) loader. As shown in FIG. 1, in a typical PC 10, the base portion of the BIOS code is stored in some type of ROM (read only memory) device on the PC's motherboard 12, such as a standard PROM 14 or a Flash Memory 16. In some configurations, this base portion may be extended using code stored in ROM BIOS chips 18 contained on one or more add-on peripheral cards 20, such as SCSI controllers and bus-mastering devices. This portion of the BIOS is stored in components that are commonly referred to as “option ROMs.” The BIOS code in peripheral card ROM BIOS chips 18 typically concerns specific functionality provided by their corresponding peripheral card and is executed during initialization of that peripheral card according to a well-defined (mostly) set of rules. In either of the foregoing configurations, all BIOS firmware is stored locally, either on the motherboard or in option ROMs on the peripheral card(s) added to a system.
In many instances, the basic functionality of a computer system platform is defined by the platform's firmware. Accordingly, in order to enhance this functionality, corresponding code needs to be added to or modified in the firmware. In today's PC's, this may be accomplished by either replacing the BIOS chip(s) on the motherboard (and/or peripheral cards), or, if the BIOS code is contained in rewritable chips (e.g., Flash Memory), executing a BIOS update software program that rewrites (overwrites) the BIOS code.
Both of these methods may be prone to error. Replacement of a BIOS chip by a novice user may lead to several problems, including improper insertion of the new chip, damage of the new chip, damage of the socket, static electricity damage to the new chip and/or existing chips on the motherboard. Popular methods for updating the BIOS code stored on a flash component also have risks. For instance, a user may try to update the BIOS code with an inappropriate set of new code, or a crash could occur in the middle of the update process. Typically, the BIOS code will be stored as a monolithic chunk of code that gets replaced in its entirety by a new monolithic chunk of code. When the BIOS code is stored on a flash component, the memory blocks corresponding to the portions of memory that are to contain the new BIOS code must first be cleared (i.e., reset to all 1's) prior to rewriting the memory. This clearing process wipes out the existing BIOS code. As a result, if a failure occurs in the middle of a rewrite or update, the BIOS code will be corrupt. Suppose a power system failure occurs that causes the user to have to reboot the computer system. Since the BIOS code is typically needed to complete the boot process, the user may not be able to boot the computer system to fix the problem, or an emergency repair disk (that the user often doesn't have) may be need to enable the problem to be fixed.